For various space vehicle maneuvers and experiments in space, particularly in low earth orbits, it is necessary to control the attitude and compensate for the drag on the vehicle while it is in orbit. In particular, these requirements are critical for experiments where telescopes and other viewing instruments are used and it is necessary to keep these instruments oriented in a precise direction.
This invention relates to a propulsion system which utilizes cryogenic helium, already on board the space vehicle for cooling an experiment package, for the additional purpose of meeting in-orbit propulsion requirements of the vehicle.
Accordingly, an important object of the present invention is to provide a propulsion system for a space vehicle utilizing boil-off gas of the on-board supply of liquid helium as a propellant without adversely affecting the temperature of the experiment package which is being cooled by the helium.
Still another important object of the present invention is to provide a simplified propulsion system which has few components and which utilizes components already existing on a space vehicle.